Soviet troops are withdrawing from Afghanistan, nine years after they swept into the country.

A convoy of Soviet armoured vehicles travelled the 260-mile (418km) journey to the USSR border while other soldiers left aboard an Ilyushin 76 transport aircraft.

Earlier, the Soviet government had announced the departure of the last troops although snow had delayed a five-day airlift from the Afghan capital Kabul.

The journey is especially dangerous on the Salang Pass through the Hindu Kush Mountains, where more than 10,000 mujahideen operate.

The mujahideen - Afghan Islamic fighters - have been involved in heavy battles to try to force a Soviet retreat.

Huge snow drifts are blocking the southern approaches to the pass, while the descent on the northern side is a wall of ice.

I've been waiting for this day for 18 months. Not everyone managed to make it

Lieutenant Aleksandr Korotkin

Russian forces are not alone in leaving Afghanistan. Families of Afghan refugees have been crossing the border into Pakistan.

Border guards have reported that a dozen families have crossed through the Khyber Pass in the last few hours.

Over the past two months, up to 20,000 have fled heavy fighting between the mujahideen and Soviet troops.

A handful of foreign correspondents have been allowed to join the Soviet convoy leaving Kabul, but only for the relatively safe last stretch of the journey, which has been secured by soldiers.

President Sayid Mohammed Najibullah's Soviet-backed Afghan government has acknowledged the complete withdrawal of soldiers with a brief statement.

"I express my appreciation to the people and government of the Soviet Union for all-round assistance and continued solidarity in defending Afghanistan," the president said.

Ahead of the departure, the mujahideen fired four rockets at the capital, with three landing in the airport area and the fourth on shops.

At Kabul's airport, most international and domestic flights are arriving and departing as usual.

According to latest BBC reports, Kabul is surrounded by a mujahideen force of around 30,000, with the city under artillery and rocket "bombardment".

Machine-gun and artillery fire could be heard during the night and this morning while a sign at the British Embassy reads "closing down temporarily". The American embassy has put up a sign which says "extended holidays for all staff - date of return not fixed".

A diplomat has reported that President Najibullah, although tired, is still defiant and is determined to play a role in the future of Afghanistan.

The Soviet daily newspaper Trud has revealed that some garrisons have been looted.

The return of the Red Army coincides with the decision by Russian President Mikhail Gorbachev to cut the Soviet armed forces by up to 500,000, with the Kremlin emphasising the heroism of those who fought in the war.

On the streets of Kabul there is a heavier presence of armed police and queues for bread are as long as ever.

On 24 December, 1979, President Leonid Brezhnev sent in troops to support the struggling communist government.

Thousands of Soviet troops intervened to prop up the pro-communist regime, leading to a major confrontation that drew in the US and Afghanistan's neighbours.

During the Soviet occupation about a million Afghans lost their lives as the Red Army tried to impose control and millions more fled abroad as refugees. Soviet deaths were estimated to be around 15,000.

The Soviet authorities hailed the withdrawal from Afghanistan as a victory although many people felt the exit marked a major humiliation of the Red Army's military power.

The civil war continued following the Soviet withdrawal, as the mujahideen pushed to overthrow President Najibullah, who was toppled in 1992.